Consider a two dimensional electron structure concentration

Consider a two dimensional electron structure concentration four an n - ALGaAs - intrinsic G_A A_S heterojunction. Consider N - AL_a3 G_a_0.7 As doped to 10^+18[cm^-3] and having a thickness of 500[R]. Assume an undoped space layer of 20[A]. Let_B = 0.85[v] and (Delta E_c/q) = 0.22[v]. The relative dielectric constant of AL_0.8 Ga_0.7 As is N = 12.2. Determine: The two - dimensional electron concentration, n_s. The type of the transistor?

Solution

4.2)

For the given question above..the transistor that is used is a High-electron-mobility transistor, also known as heterostructure FET ormodulation-doped FET (MODFET), is a field-effect transistor incorporating a junction between two materials with different band gaps (i.e. a heterojunction) as the channel instead of a doped region (as is generally the case for MOSFET). A commonly used material combination is GaAs with AlGaAs, though there is wide variation, dependent on the application of the device. Devices incorporating more indium generally show better high-frequency performance, while in recent years, gallium nitride HEMTs have attracted attention due to their high-power performance. HEMT transistors are able to operate at higher frequencies than ordinary transistors, up to millimeter wavefrequencies, and are used in high-frequency products such as cell phones, satellite television receivers, voltage converters, andradar equipment.